A hybrid vehicle may be electrically coupled to a stationary power grid when the vehicle is not being driven to supply low cost and low carbon emission fuel (e.g., electrical charge) to the vehicle. The vehicle may operate for a time using the electrical charge provided by the stationary power grid. Nevertheless, if the vehicle is driven for an extended period of time, an internal combustion engine may be started to propel the vehicle. The engine may also recharge the vehicle's battery when the battery state of charge (SOC) is low. However, vehicle emissions may be higher than desired when the engine is cold started since cold start emissions are often higher than vehicle emissions when the vehicle's engine is restarted warm.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for heating a vehicle, comprising: selectively operating a vehicle heat pump when the vehicle is electrically coupled to a stationary electrical power grid; and providing heat to an engine via the vehicle heat pump.
By heating coolant supplied to an engine via a heat pump, it may be possible to provide the technical result of reducing engine friction and engine emissions after an engine has not started for a period of time. Since the vehicle is electrically coupled to a stationary electrical power grid, electrical power generated at lower cost and lower emissions levels may provide a cost effective way of reducing vehicle emissions during engine starting. Additionally, the heat pump may be selectively operated when the vehicle is not electrically coupled to a stationary electrical power grid to warm the engine before engine starting. For example, the heat pump may be activated during regenerative braking to heat the engine so that the engine may be prepared to start at conditions that may reduce engine emissions as compared to if the engine was near ambient temperature during engine starting.
The present description may provide several advantages. For example, the approach may improve vehicle emissions. Additionally, the approach may reduce fuel consumption while maintaining passenger comfort. Further, the approach may improve a vehicle's regenerative braking capability.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.